Phonetic drift reveals interconnected phonological representations in simultaneous bilinguals: A case study of English and Czech stop consonants

Abstract

Purpose: The interconnectedness of phonological categories between the two languages of early bilinguals has previously been explored using single-probe speech production and perception data. Our goal was to tap into bilingual phonological representations in another way, namely via monitoring instances of phonetic drift due to changes in language exposure. Design: We report a case study of two teenage English–Czech simultaneous bilinguals who live in Canada and spend summers in Czechia (Czech Republic). Voice onset time (VOT) of word-initial voiced and voiceless stops was measured upon the bilinguals’ arrival to and before their departure from a two-month stay in Czechia. Data and Analysis: Each bilingual read the same set of 71 Czech and 58 English stop-initial target words (and additional fillers) at each time of measurement. The measured VOT values were submitted to linear mixed effects models, assessing the effects of target language, measurement time, and underlying voicing. Findings/Conclusions: After the immersion in a Czech-speaking environment, for both speakers the count of voiced stops realized as prevoiced (i.e., having negative VOT) increased and the measured VOT of voiced stops (appearing different for English and Czech initially) drifted towards more negative (more Czech-like) values in both languages, while no change was detected for the voiceless stops of either English (aspirated) or Czech (unaspirated). The results suggest that the bilinguals maintain three-way VOT distinctions, differentiating voiceless aspirated (English), voiceless unaspirated (Czech), and voiced (English–Czech) stops, with connected bilingual representations of the voiced categories. Originality: Data on phonetic drift in simultaneous bilinguals proficient in their two languages have not previously been published. Significance/Implications: We show that observing phonetic shifts due to changes in the ambient linguistic environment can be revealing about the organization of phonological space in simultaneous bilinguals.